Date: Tue, 12 Apr 2005 11:19:34 -0600
From: Dan Long
Subject: Re: 2.5m obslog 20050411 (MJD 53472)
>                        APACHE POINT OBSERVATORY SDSS 2.5M
>
>                                  OBSERVING LOG
>                              Monday April 11, 2005
>
>                                   (MJD 53472)
>
>---=== OBSERVING TEAM ===---
>
>         Atsuko Nitta
>         Howard Brewington
>         Mike Harvanek (swing)
>
>---=== OBSERVING PLAN ===---
>
>         Science!
>
>---=== OBSERVING SUMMARY ===---
>
>Few clouds with very good seeing made it a very good spectro night.
>Jen, we got lots of data for you to take care of. We finished 8 plates
>and 1/3 on the 9th.
>
>During the last plate when we tried to gotoField, we saw many
>error message saying that the command was not valid and
>check for spelling. I have saved the tcclog around the time of the
>this at
>
>ank@sdsshost:bummer.log
>
>This cost us about 20 min.
>
Wow!  Somehow a truly impressive 48 minutes worth of TCC responses
between TAI of about 4620017233 and 4620020092 were sent to a telrun
session. This happened about three quarters of a second after the
track command for the last plate was issued at 10:56:31Z (~4620020188
TAI).  The TCC spit out complaints over the next 18 seconds as it
processed all the bogus "commands".  Amazingly, it looks like the
track continued unaffected until an axis stop was sent at 10:57:12Z.
If I understand the way the TCC tags input it appears that session 14
is where the garbage came from.  I don't know how to tell what
machine that corresponds to.  However looking at other input from
session 14 it appears to be the laptop at the telescope.  There are
lots of axis inits and at the end of the night a track 121,6 mount
which is not usually done from anywhere else.
I have in the past accidentally hit a button on the track ball mouse
which selected some text from the TCC window (the one usually active)
then pasted it before I realized something had been selected.
However, unless the window scrolls back very quickly when the
selection region hits the top of what is currently visible, I don't
see how such a large volume of data could have been accidentally (or
indeed even on purpose) pasted by a person.
So it looks like there were an enormous amount of TCC responses sent
from the telrun session at the laptop.  How that happened is still a
mystery.
				Cheers,
				  Dan